An in vitro study on the inhibition and ultrastructural alterations of Candida albicans biofilm by zinc oxide nanowires in a PMMA matrix

Constanza Apip; Alejandra Martínez; Manuel Meléndrez; Mariana Domínguez; Teresita Marzialetti; Ricardo Báez; Gabriela Sánchez-Sanhueza; Andrés Jaramillo; Alfonso Catalán

doi:10.1016/j.sdentj.2021.08.006

An in vitro study on the inhibition and ultrastructural alterations of Candida albicans biofilm by zinc oxide nanowires in a PMMA matrix

Saudi Dent J. 2021 Dec;33(8):944-953. doi: 10.1016/j.sdentj.2021.08.006. Epub 2021 Aug 5.

Authors

Constanza Apip¹, Alejandra Martínez¹, Manuel Meléndrez², Mariana Domínguez³, Teresita Marzialetti⁴, Ricardo Báez⁵, Gabriela Sánchez-Sanhueza⁶, Andrés Jaramillo⁷, Alfonso Catalán⁸

Affiliations

¹ Oral Prosthetic Rehabilitation Program, Department of Restorative, School of Dentistry, University of Concepción, 1550 Roosevelt, Concepción 4070409, Chile.
² Hybrid Material and Polymer Lab, Department of Materials Engineering, Faculty of Engineering, University of Concepción, Concepción, Chile.
³ Department of Microbiology, Faculty of Biological Science, University of Concepción, Casilla 160C, Concepción 4070409, Chile.
⁴ Department of Chemical Engineering, Faculty of Engineering, University of Concepción, 219 Edmundo Larenas, Concepción 4070409, Chile.
⁵ Department of Physics, Faculty of Physical and Mathematical Sciences, University of Concepción, 219 Edmundo Larenas, Concepción 4070409, Chile.
⁶ Department of Restorative Dentistry, School of Dentistry, University of Concepción, 1550 Roosevelt St, Concepción 4070409, Chile.
⁷ Department of Mechanical Engineering, Universidad de La Frontera, 01145 Francisco Salazar, Temuco 4780000, Chile.
⁸ Removable Prosthetics, Department of Restorative Dentistry, School of Dentistry, University of Concepción, 1550 Roosevelt St, Concepción 4070409, Chile.

Abstract

Objectives: The purpose of this study was (i) to investigate whether nanocomposite poly(methyl-methacrylate)-zinc oxide nanowires (PMMA-ZnO-NWs) have C. albicans antibiofilm activity; (ii) to evaluate the interaction between components of the nanocomposites based on PMMA-ZnO-NWs by Raman spectroscopy; and (iii) to assess ultrastructural alterations.

Design: Sixty-eight rectangles (17 PMMA (control) and 51 PMMA-ZnO-NWs (250, 500, 1000 ppm ZnO nanowires) were fabricated. C. albicans ATCC 10231 and a C. albicans clinical strain were tested. Adherence, biofilm formation and ultrastructural alterations were assessed by transmission electron microscopy. Raman mapping images and spectra were analyzed using main component analysis.

Results: Nanocomposite PMMA-ZnO-NWs inhibited the formation of C. albicans biofilms 94% at 1000 ppm and 80% at 500 ppm against both C. albicans strains. PMMA-ZnO-NWs induced ultrastructural alterations, including cell wall damage and disorganization of the cytoplasmic membrane, resulting in cell lysis. Raman spectroscopy showed new vibrational modes (300-365-485-600 cm^-1) for PMMA and ZnO-NW interactions.

Conclusions: PMMA-ZnO-NWs inhibited C. albicans dose-dependent biofilm formation and led to changes in the structures and cell membrane. Raman spectroscopy showed chemical interactions between ZnO-NWs and PMMA, as suggested by the appearance of new bands at 301 and 485 cm^-1.

Keywords: Biofilm; C. albicans; Nanowires; Poly(methyl-methacrylate); Ultrastructural alteration; Zinc oxide.